Filip Meysman, Stijn Bruers, Jack Middelburg

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Thermodynamics and Ecology from Carnot engines
to ecosystems
Filip Meysman, Stijn Bruers, Jack Middelburg
Netherlands Institute of Ecology
(NIOO-KNAW) Centrum Estuarine en Marine
Ecology Department Ecosystem Studies Korringaweg
7, 4401 NT Yerseke
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Outline of the presentation

• Thermodynamics and ecology Two fields in a state
  of confusion? (personal view)
• From Carnot engines to dissipative structures
• Many dissipative structures boycotting each
  other turbulence and ecosystems (intro to
  Stijns work)

Eurandom 2005
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Part 1 Thermodynamics and Ecology two fields
in a state of confusion?
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Thermodynamics and ecology?
Theory

• Ecosystems are macroscopic physical systems
• Thermodynamics is that part of the physics theory
  that deals with macroscopic phenomena (not too
  small -gt quantum, not too big -gt relativity)
• Conclusion thermodynamic principles should in
  theory be applicable to ecology

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Ecologists liberal use of thermodynamics

• Fuzzy terminology using terms without proper
  definitions (e.g. organisms are dissipative
  structures)
• Using concepts out of context

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Ecologists do not like entropy
A range of other y-ending properties are defined
to characterize the functioning of an ecosystem

• Emergy (Odum,1983)
• Ascendency (Ulanowicz, 1986)
• Exergy
• .

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Are ecologists the only one to blame?
Thermodynamics comes in many different flavours

• Equilibrium thermodynamics (Carnot, Clausius,
  Gibbs)
• Linear non-equilibrium thermodynamics (Onsager)
• Rational thermodynamics (Truesdell)
• Far-from-equilibrium thermodynamics (Prigogine)
• Extended thermodynamics
• Finite-time thermodynamics

These different theories are not necessarily
inter-consistent, nor is the link clear between
them.
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Speaking in many tongues
The Second Law

• 29 different formulations of the Second Law
• Bluff you way into the Second Law of
  Thermodynamics (Uffink, 2001)
• Essential conflict between the Kelvin-Planck
  formulation and that of Caratheodory (1909)
  remains unsolved
• There is more than just terminological confusion

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Present theory is subjective ?
The First Law
(Energy change Heat work)
environment
Adiabatic expansion
system
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Link between thermodynamics and ecology
Summary

• Thermodynamic modeling theory itself is not fully
  mature and crystallized
• Sloppy application of thermodynamics in ecology
  (based on intuition, with little quality
  control)

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Part 2 From Carnot engines to dissipative
structures
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Carnot engine
High-temperature reservoir
1 Thermal conduction over Infinitely small
temperature gradients 2 No frictional losses
QH
Working fluid cycle
Pump
QL
Low-temperature reservoir
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Analysis Carnot engine
Work produced in one cycle
Heat discarded in low-temp-res
Entropy production per cycle
Power output
Entropy production
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Steam engine
Two types of entropy production 1 Thermal
conduction over finite temperature gradients 2
Frictional losses momentum Transfer over
velocity gradient
QH
Boiler
Working fluid
Condenser
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Steam engine steady-state analysis
Work produced in one cycle
Heat discarded in low-temp-res
Entropy production per cycle
Power output
Entropy production
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Freak engine
QH
Boiler
All the work produced is delivered back to the
engine to increase the cycling frequency
Working fluid cycle
Condenser
QH
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Steady-state analysis Freak engine
Work produced in one cycle
Heat discarded in low-temp-res
Entropy production per cycle
Power output
Entropy production
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Two modes of operation
Freak engine does cycle -gt
Freak engine does not cycle
Positive feedback
Th
Th
Kinetic energy
Friction
Tl
Tl
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Freak engine Entropy production
Cycling mode stable branch
Total entropy production
No-cycling mode stable branch
Critical threshold
Driving force
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Freak engine dissipative structure
Atmospheric fluid dynamics
QH
Working fluid cycle
Organisms Ecosystems
QH
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Hurricane upside down Freak engine
Warm sea water
Positive feedback
Warm air
Kinetic energy
Turbulence
Cold air
Cold stratosphere
Driving force
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Benard-Rayleigh cell Entropy production
Total entropy production
Thermal convection stable branch
Thermal conduction stable branch
Critical threshold
Driving force
Nature abhors a gradient Schneider Sagan
(2005)
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Bacteria freak engine
Glucose reservoir
Positive feedback
Glucose
Bacterial growth in chemostat
Bacterial biomass
Cell Turn-over
CO2
CO2 reservoir
Driving force
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Bacterial growth in chemostat
1. Respiration
CO2
Gluc
Glucose reservoir
ATP
ADP
Positive feedback
Glucose
2. Biomass synthesis (work)
Bacterial biomass
Gluc
Biomass
Cell Turn-over
CO2
ADP
ATP
3. Biomass turn-over (friction)
Waste reservoir
Biomass
Gluc
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Bacterial growth in chemostat
Mass balance reactor glucose (Ch)
Exchange with reservoirs
Glucose consumption
Recycling Biomass turn-over
Mass balance reactor CO2 (Cl)
Exchange with reservoirs
Respiration
Mass balance bacterial biomass (B)
Biomass turn-over
Growth
See presentation Stijn Bruers
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Two modes of operation
Biological oxidation
Chemical oxidation
Positive feedback
Ch
Ch
Bacterial biomass
Turn-over
Cl
Cl
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Entropy production in chemostat
Overall conversion
Total entropy production
Bacterial oxidation stable branch
This graph only shows the effect of one organism
feeding on an abiotic food source!
Pure chemical oxidation stable branch
Critical threshold
Driving force
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Part 3 Many dissipative structures boycotting
each other
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Turbulent cascade
Warm air
Large Eddy
Smaller Eddy
Smaller Eddy
Smaller Eddy
Cold air

• Smaller eddies feeding on larger eddies, on to
  viscous dissipation

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Energy transport from tropics to polar regions
Emission terrestrial radiation
Incoming solar radiation
Poles
Tropics
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Simplified equation set
Linearization of Wiens Radiation Law leads to
(Kleidon and Lorenz, 2005)
Temperature tropics
Tropic temperature
Pole temperature
Temperature pole
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Energy transport from tropics to polar regions
Emission terrestrial radiation
Incoming solar radiation
Poles
Tropics
Net energy transfer
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Maximum entropy production
Temperature tropics
Tropic temperature
Complete universe
Pole temperature
Atmospheric circulation
Temperature pole
Eurandom 2005
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Maximal entropy production
To good to be true?

• MEP value of heat transport coefficient k 2 W
  m-2 K-1
• MEP state conforms with observations on the Earth
  climate system equator-pole temperature profile,
  intensity of athmospheric circulation, cloud
  cover (Paltridge 1975)
• Confirmed by general circulations model
  simulations (Shimokawa and Ozawa, 2001)
• MEP on other planets Mars and Saturns moon
  Titan

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Food chain in food web marine sediments
Organic matter from water column
Bacteria
Ciliates
Copepods
Predator polychaet
CO2

• Larger predators feeding on smaller prey

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Food web in a marine sedimens
Input from water column
Accumulation deeper sediments
Accumulation deeper sediments
Food web
Organic matter from water column
CO2
Net conversion
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Entropy production.
Equations for a chemostat ecosystem are
completely analogous
Complete universe
Food web conversion
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Conclusions
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Steam engine Dynamic operation
Energy
Kinetic energy
Internal energy condenser
Internal energy boiler
High temp reservoir
Kinetic energy
Low temp reservoir
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Freak steam engine dissipative structure
Energy balance warm air currents
Warm Seawater
Q
Conversion
Transfer from sea water
Positive feedback
Energy balance cold air currents
Kinetic energy
Transfer from warm air
Transfer to stratosphere
Frictional loss
Q
Kinetic energy balance
Cold stratosphere
Frictional force
Driving force
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